RISK SENSITIVE FORAGING BEHAVIOR OF THE ROUND-EARED ELEPHANT SHREW (MACROSCELIDES PROBOSCIDEUS)

We examined the risk-sensitive foraging behaviour of the round-eared e lephant shrew by open-economy choice experiments, in which animals wer e deprived of food immediately prior to experiments but given food ad libitum afterwards, to test the energy budget rule. The energy budget rule states that if an animal's (daily) energy budget is negative it s hould behave in a risk-prone manner. A risk-prone elephant shrew shoul d select food from a more variable rather than a constant feeding stat ion, although both feeding stations yield the same average return. The choice of a variable station can indicate the degree to which an anim al is an energy-shortfall minimizer. Elephant shrews running below ene rgy requirement did not choose feeding stations in accordance with the rule. Under laboratory conditions, approximating either average summe r or winter temperatures, elephant shrews showed risk-averse behaviour . A polycyclic activity profile, the ability to switch the diet, and g reater than expected physiological control over energy balance, may fa vour a continuously foraging animal such that short-term energy defici ts are minimized. We argue that, under these conditions, a risk-averse response to reward-size variance is expected, because an elephant-shr ew may not reliably perceive those circumstances under which risk-pron e behaviour should be adopted.